/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.test.web.servlet.htmlunit;

import com.gargoylesoftware.htmlunit.*;
import com.gargoylesoftware.htmlunit.util.Cookie;
import org.apache.http.impl.cookie.BasicClientCookie;
import org.springframework.lang.Nullable;
import org.springframework.mock.web.MockHttpServletResponse;
import org.springframework.mock.web.MockHttpSession;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.RequestBuilder;
import org.springframework.test.web.servlet.ResultActions;
import org.springframework.util.Assert;

import java.io.IOException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

/**
 * {@code MockMvcWebConnection} enables {@link MockMvc} to transform a
 * {@link WebRequest} into a {@link WebResponse}.
 * <p>This is the core integration with <a href="http://htmlunit.sourceforge.net/">HtmlUnit</a>.
 * <p>Example usage can be seen below.
 *
 * <pre class="code">
 * WebClient webClient = new WebClient();
 * MockMvc mockMvc = ...
 * MockMvcWebConnection webConnection = new MockMvcWebConnection(mockMvc, webClient);
 * webClient.setWebConnection(webConnection);
 *
 * // Use webClient as normal ...
 * </pre>
 *
 * @author Rob Winch
 * @author Sam Brannen
 * @see org.springframework.test.web.servlet.htmlunit.webdriver.WebConnectionHtmlUnitDriver
 * @since 4.2
 */
public final class MockMvcWebConnection implements WebConnection {

    private final Map<String, MockHttpSession> sessions = new HashMap<>();

    private final MockMvc mockMvc;

    private final String contextPath;

    private WebClient webClient;


    /**
     * Create a new instance that assumes the context path of the application
     * is {@code ""} (i.e., the root context).
     * <p>For example, the URL {@code http://localhost/test/this} would use
     * {@code ""} as the context path.
     *
     * @param mockMvc   the {@code MockMvc} instance to use; never {@code null}
     * @param webClient the {@link WebClient} to use. never {@code null}
     */
    public MockMvcWebConnection(MockMvc mockMvc, WebClient webClient) {
        this(mockMvc, webClient, "");
    }

    /**
     * Create a new instance with the specified context path.
     * <p>The path may be {@code null} in which case the first path segment
     * of the URL is turned into the contextPath. Otherwise it must conform
     * to {@link javax.servlet.http.HttpServletRequest#getContextPath()}
     * which states that it can be an empty string and otherwise must start
     * with a "/" character and not end with a "/" character.
     *
     * @param mockMvc     the {@code MockMvc} instance to use (never {@code null})
     * @param webClient   the {@link WebClient} to use (never {@code null})
     * @param contextPath the contextPath to use
     */
    public MockMvcWebConnection(MockMvc mockMvc, WebClient webClient, String contextPath) {
        Assert.notNull(mockMvc, "MockMvc must not be null");
        Assert.notNull(webClient, "WebClient must not be null");
        validateContextPath(contextPath);

        this.webClient = webClient;
        this.mockMvc = mockMvc;
        this.contextPath = contextPath;
    }

    /**
     * Validate the supplied {@code contextPath}.
     * <p>If the value is not {@code null}, it must conform to
     * {@link javax.servlet.http.HttpServletRequest#getContextPath()} which
     * states that it can be an empty string and otherwise must start with
     * a "/" character and not end with a "/" character.
     *
     * @param contextPath the path to validate
     */
    static void validateContextPath(@Nullable String contextPath) {
        if (contextPath == null || "".equals(contextPath)) {
            return;
        }
        Assert.isTrue(contextPath.startsWith("/"), () -> "contextPath '" + contextPath + "' must start with '/'.");
        Assert.isTrue(!contextPath.endsWith("/"), () -> "contextPath '" + contextPath + "' must not end with '/'.");
    }

    private static com.gargoylesoftware.htmlunit.util.Cookie createCookie(javax.servlet.http.Cookie cookie) {
        Date expires = null;
        if (cookie.getMaxAge() > -1) {
            expires = new Date(System.currentTimeMillis() + cookie.getMaxAge() * 1000);
        }
        BasicClientCookie result = new BasicClientCookie(cookie.getName(), cookie.getValue());
        result.setDomain(cookie.getDomain());
        result.setComment(cookie.getComment());
        result.setExpiryDate(expires);
        result.setPath(cookie.getPath());
        result.setSecure(cookie.getSecure());
        if (cookie.isHttpOnly()) {
            result.setAttribute("httponly", "true");
        }
        return new com.gargoylesoftware.htmlunit.util.Cookie(result);
    }

    public void setWebClient(WebClient webClient) {
        Assert.notNull(webClient, "WebClient must not be null");
        this.webClient = webClient;
    }

    public WebResponse getResponse(WebRequest webRequest) throws IOException {
        long startTime = System.currentTimeMillis();
        HtmlUnitRequestBuilder requestBuilder = new HtmlUnitRequestBuilder(this.sessions, this.webClient, webRequest);
        requestBuilder.setContextPath(this.contextPath);

        MockHttpServletResponse httpServletResponse = getResponse(requestBuilder);
        String forwardedUrl = httpServletResponse.getForwardedUrl();
        while (forwardedUrl != null) {
            requestBuilder.setForwardPostProcessor(new ForwardRequestPostProcessor(forwardedUrl));
            httpServletResponse = getResponse(requestBuilder);
            forwardedUrl = httpServletResponse.getForwardedUrl();
        }
        storeCookies(webRequest, httpServletResponse.getCookies());

        return new MockWebResponseBuilder(startTime, webRequest, httpServletResponse).build();
    }

    private MockHttpServletResponse getResponse(RequestBuilder requestBuilder) throws IOException {
        ResultActions resultActions;
        try {
            resultActions = this.mockMvc.perform(requestBuilder);
        }
        catch (Exception ex) {
            throw new IOException(ex);
        }

        return resultActions.andReturn().getResponse();
    }

    private void storeCookies(WebRequest webRequest, javax.servlet.http.Cookie[] cookies) {
        Date now = new Date();
        CookieManager cookieManager = this.webClient.getCookieManager();
        for (javax.servlet.http.Cookie cookie : cookies) {
            if (cookie.getDomain() == null) {
                cookie.setDomain(webRequest.getUrl().getHost());
            }
            Cookie toManage = createCookie(cookie);
            Date expires = toManage.getExpires();
            if (expires == null || expires.after(now)) {
                cookieManager.addCookie(toManage);
            }
            else {
                cookieManager.removeCookie(toManage);
            }
        }
    }

    @Override
    public void close() {
    }

}
